Creep-resistant magnesium alloy

ABSTRACT

The present invention relates to a magnesium aluminum alloy with enhanced creep resistance. The alloy contains barium and calcium in low proportions, and possesses a higher creep resistance in comparison to alloys containing rare earth elements. The alloy may additionally include zinc, tin, lithium, manganese, yttrium, neodymium, cerium and/or praseodymium in proportions of up to 7% by weight, respectively.

FIELD OF THE INVENTION

The present invention relates to a creep-resistant magnesium alloy.

BACKGROUND AND PRIOR ART

Metal alloys containing magnesium are used extensively in the automotive industry, electronic industry, aerospace industry and several other technical areas. Those alloys are especially advantageous, which are high temperature creep-resistant and therefore usable in a high temperature environment.

Several different magnesium alloys have been developed and standardized, such as the magnesium alloys JIS H 5203 (MC1-MC10) and JIS H 5303 (MDC1A, MDC1B). Alloy A having the composition Mg-4% Al-2% RE (RE=rare earth elements), which has been developed by the company Dow Chemical, is also well known for high temperature use.

However, such heat-resistant magnesium alloys are quite inapplicable in casting, wherein the metal object must be cooled rapidly after shaping.

DE 44 46 898 A1 discloses creep-resistant magnesium alloys, containing: 1.5 to 10% by weight of aluminum (Al), less than 2% by weight of rare earth elements (RE), 0.25 to 5.5% by weight of calcium (Ca), the balance being magnesium. In addition, the alloy may contain 0.2 to 2.5% by weight of copper and/or zinc.

The rare earth elements contained in such alloys, however, increase the costs of the alloy.

DE 22 01 460 A1 also discloses creep-resistant magnesium alloys containing aluminum and optionally an additional element selected from calcium, zirconium, titanium, silicon, strontium, yttrium, cerium or barium. Barium and calcium in combination are not disclosed as additional elements.

SUMMARY

It is therefore the object of the present invention to provide a magnesium alloy, which is able to overcome the above mentioned disadvantages of the state of the art and, moreover, has a higher creep resistance.

The object is solved by a metal alloy containing magnesium or magnesium alloy, containing 1 to 9% by weight of aluminum (Al), 0.5 to 5% by weight of barium (Ba), 0.5 to 5% by weight of calcium (Ca), the balance being magnesium (Mg) and inevitable production-related impurities, based on the total weight of the alloy. Preferably, the inevitable production-related impurities amount in total to no more than 2% by weight, based on the total weight of the alloy. The proportion of aluminum is preferably 2 to 7% by weight, more preferably 3 to 6% by weight. The proportion of barium is preferably 1 to 4% by weight, more preferably 1.5 to 3% by weight. The proportion of calcium is preferably 1 to 4% by weight, more preferably 1.5 to 3% by weight.

The magnesium alloy of the invention may additionally include zinc, tin, lithium, manganese, yttrium, neodymium, cerium and/or praseodymium in proportions of up to 7% by weight, respectively.

The magnesium alloy of the invention may be used in a multiplicity of application areas; preferably it is used in the production of components for automotives, vessels and/or aeroplanes, more preferably in the production of power trains and components thereof.

BRIEF DESCRIPTION OF THE DRAWING

The drawing is a graph showing creep deformation as a function of time for two magnesium alloys of the invention.

DETAILED DESCRIPTION

The invention is further illustrated with reference to the attached FIGURE. In FIG. 1, the creep deformation as a function of time with an applied strain of 80 MPa and a temperature of 200° C. of two inventive magnesium alloys (ABC alloys) containing about 4% by weight of aluminum, about 2% by weight of barium and about 1% by weight of calcium (ABC421) and about 4% by weight of aluminum, about 2% by weight barium and about 2% by weight of calcium (ABC422), respectively, is shown in comparison to a conventional alloy AE42, wherein E denotes rare earth elements, and an alloy produced by the company Dead Sea Magnesium under the name of MRI230D, which contains rare earth elements in addition to aluminum and calcium.

The inventive alloys have a considerably lower creep deformation than the respective comparison alloys. This leads to the conclusion that, with constant strain, the temperature may be increased even further, or that a component may be strained for considerably prolonged times. 

1. Magnesium alloy, containing the following ingredients, based on total weight of the alloy: 1 to 9% by weight of aluminium 0.5 to 5% by weight of barium 0.5 to 5% by weight of calcium and the balance being magnesium.
 2. The magnesium alloy according to claim 1, characterized in that it additionally includes zinc, tin, lithium, manganese, yttrium, neodymium, cerium and/or praseodymium in proportions of up to 7% by weight, respectively.
 3. The magnesium alloy according to claim 1, characterized in that the proportion of aluminum is 2 to 7% by weight.
 4. The magnesium alloy according to claim 1, characterized in that the proportion of barium is 1 to 4% by weight.
 5. The magnesium alloy according to claim 1, characterized in that the proportion of calcium is 1 to 4% by weight.
 6. A method for the production of components of automotives, vessels and/or airplanes, comprising making the components from the magnesium alloy of claim
 1. 7. A method for the production of power trains or components thereof, comprising making the components from the magnesium alloy of claim
 1. 8. The magnesium alloy according to claim 1, characterized in that the proportion of aluminum is 3 to 6% by weight.
 9. The magnesium alloy according to claim 1, characterized in that the proportion of barium is 1.5 to 3% by weight.
 10. The magnesium alloy according to claim 2, characterized in that the proportion of barium is 1.5 to 3% by weight.
 11. The magnesium alloy according to claim 1, characterized in that the proportion of calcium is 1.5 to 3% by weight.
 12. The magnesium alloy according to claim 2, characterized in that the proportion of calcium is 1.5 to 3% by weight.
 13. The magnesium alloy according to claim 3, characterized in that the proportion of calcium is 1.5 to 3% by weight.
 14. A method for the production of components of automotives, vessels and/or airplanes, comprising making the components from the magnesium alloy of claim
 2. 15. A method for the production of components of automotives, vessels and/or airplanes, comprising making the components from the magnesium alloy of claim
 3. 16. A method for the production of components of automotives, vessels and/or airplanes, comprising making the components from the magnesium alloy of claim
 4. 17. A method for the production of components of automotives, vessels and/or airplanes, comprising making the components from the magnesium alloy of claim
 5. 18. A method for the production of power trains or components thereof, comprising making the components from the magnesium alloy of claim
 2. 19. A method for the production of power trains or components thereof, comprising making the components from the magnesium alloy of claim
 3. 20. A method for the production of power trains or components thereof, comprising making the components from the magnesium alloy of claim
 4. 